BACKGROUND: Cardiac autonomic dysfunction is associated with heart failure (HF). Reduced heart rate recovery (HRR) indicates impaired parasympathetic reactivation after physical activity. Heart rate recovery 60 seconds after peak effort (HRR) is linked to autonomic dysfunction, but data on its relevance across HF phenotypes are scarce. This study aimed to identify clinical determinants of HRR in an HF cohort and assess its relationship with clinical outcomes. METHODS: Data from the MyoVasc study (NCT04064450; N=3289) were analyzed. Participants underwent standardized clinical phenotyping including cardiopulmonary exercise testing. HRR was defined as the heart rate decline 60 seconds after exercise termination. Clinical determinants of HRR were evaluated using multivariate regression, whereas Cox regression analyses assessed all-cause death and worsening of HF. RESULTS: The analysis sample comprised 1289 individuals (median age, 66.0 [interquartile range {IQR}, 58.0-73.0] years, 30.4% women) ranging from stage B to stage C/D according to the universal definition of HF. Age, sex, smoking, obesity, peripheral artery disease, and chronic kidney disease were identified as determinants of HRR. HRR showed a strong association with all-cause death (hazard ratio [HR], 1.56 [95% CI, 1.32-1.85]; <0.0001) and worsening of HF (HR, 1.36 [95% CI, 1.10-1.69]; =0.0052) independent of age, sex, and clinical profile. Sensitivity analysis showed a stronger association with worsening HF in HF with preserved left ventricular ejection fraction (=0.027). CONCLUSIONS: HRR was associated with clinical outcome in chronic HF. Because it showed a stronger association with outcomes in HF with preserved ejection fraction, future research should consider phenotype-specific differences.